1996 Lexus SC 400FACTORY OEM SERVICE PROCEDURE

ECM Ground Circuits

ECM is located underneath top of passenger-side carpet (behind glove box) and is mounted to floor panel. Measure resistance between engine (ground) and specified terminals at ECM connector. See ECM GROUND CIRCUITS table. If resistance is more than one ohm, repair ground circuit. If resistance is one ohm or less, ground circuit is okay (ECM may be faulty).

ECM GROUND CIRCUITS

Application Type ECM Connector (1) (1) ECM Terminals No. (Wire Color)
ECM Ground Circuits "B" (2) 69 (Brown)
" "B" (2) 79 & 80 (White/Black)
(1) See Figure.
(2) Attached to left cylinder head.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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